Irrational Number Line Games, LLC
So, some basic little ingredients here:
The little bit in the center is the dial from inside one of the bases. It doesn't really matter what you are using. If you have some other pieces of scrap, that will work as well (more on this later), the point is you have something that you could have thrown away, but didn't because you could use it. Well, now's the time to use it.
Now rinse and repeat!
I use lots of different configurations to give me an irregular interior "hive" or "non-euclidian" pattern.
Beyond the basic columns, there are two balls in the configuration. One is an old optical trackball the other is a painted up ping pong ball.
Here's a ground view, which you'll probably never have (unless you use a camera), but it shows the lines of fire being blocked by different configurations.
You can also see some old paint bottles used as columns and a large juice bottle cap.
Here's a close up showing some figures in the mix.
Since the CDs are round, and you can pack them in using a hex pattern, you can also have some rules for rotating the walls too.